1. Field of the Invention
The present invention relates to an electronic apparatus having a structure in which a substrate provided with electronic parts is accommodated in a hermetically sealed casing.
2. Description of the Related Art
A memory device that is used as an AVTR (Airborne Video Tape Recorder) aboard an airplane, for instance, can be replaceably equipped with a recording medium cartridge inside a box-like casing that is hermetically sealed so as to cope with fluctuations of atmospheric pressure with altitude, and prevent adverse influence from humidity, dust, fungus, and other environmental factors. In recent years, recording media of this type are shifting from video tape to memory cards that contain semiconductor memories, such as PCMACIA (Personal Computer Memory Card International Association) cards. One or a plurality (2 to 7) of memory cards can be accommodated in one cartridge, depending on the required memory size.
In the above memory device into which a memory cartridge is replaceably inserted, a substrate equipped with an electronic part such as a CPU is also accommodated in the casing. An electronic part such as a CPU has a large quantity of heat generation, and therefore needs to be cooled down.
Methods for cooling a substrate accommodated in a hermetically sealed casing include: 1) a method of stirring the air in the casing; 2) a method of attaching an electronic part such as a CPU directly to the inner wall of the casing; 3) a method of conducting heat to the casing by connecting the heat generating portion to the casing by a heat pipe; and 4) a method of cooling the heat generating portion by employing a Peltier element or a heat exchanger.
However, by the method 1) of stirring the air inside the casing, external air cannot be introduced into the hermetically sealed casing, and the inner air cannot be released from the casing. Because of this, it is difficult to cool down even by employing a fan for stirring the air. Furthermore, with an electronic part such as a CPU having a large heat value, there is a problem that the mean temperature is below the allowable temperature range even after the stirring of the air inside the casing.
As for the method 2), it is not realistic to attach an electronic part such as a CPU directly to the inner wall of the casing.
As for the methods 3) and 4), the production costs are high, because a heat pipe, a Peltier element, and a heat exchanger are expensive. Also, since those components are relatively large in size, it is difficult to secure a wide enough space, allowing less freedom in design.
The memory cartridge is provided with a multipolar male connector at the end portion of the insertion side. By inserting the memory cartridge, the multipolar male connector is connected to a multipolar female connector located on the substrate in the memory device. When the cartridge is replaced by a new one, the cartridge is guided and inserted through a cartridge inlet, and the multipolar female connector located in the memory device is engaged with and electrically connected to the multipolar male connector.
In this cartridge inserting operation, the cartridge is first manually inserted into the cartridge inlet, and then pushed further into the device by the closing of an open-close cover of the cartridge inlet, thereby engaging the multipolar male connector with the multipolar female connector.
In the above device, however, the cartridge is pushed in the inserting direction by closing the cover after the insertion of the cartridge, so that the multipolar male connector is engaged with the multipolar female connector. In this manner, fine adjustment cannot be made to the insertion position, compared with a case of manually handling the cartridge. As a result, the multipolar male connector might deviate from the multipolar female connector.
Since the engagement between the multipolar male connector and the multipolar female connector is made deep inside the cartridge inlet, an operator cannot check whether or not the engagement is successful. Therefore, it is necessary for an operator to close tightly the cover of the cartridge inlet so as to engage the multipolar male connector to the multipolar female connector. However, if the multipolar male connector is brought into contact with the multipolar female connector in a deviated state, either or both of the connectors might be deformed.
A general object of the present invention is to provide electronic apparatuses in which the above disadvantages are eliminated.
A more specific object of the present invention is to provide an electronic apparatus in which a temperature rise in a hermetically sealed casing is restricted so as to obtain high reliability.
An electronic apparatus in accordance with the present invention includes: a fan that is located inside a casing and generates air current passing through circuit substrates; an air current guide unit that is located on the inner wall of the casing and extends in the direction of guiding the air current toward the suction side of the fan; and a plurality of radiation fins that are located outside the casing. With this electronic apparatus, the air current can be generated in the casing so as to average the inner temperature of the casing, without a costly component such as a heat pipe, a Peltier element, or a heat exchanger. In this manner, the heat generated in the casing can be dispersed all over the casing, and the dispersed heat is then released to the outside through the radiation fins. Thus, the inner temperature of the casing can be cooled down below the allowable temperature range.
Further, a wall of the casing facing the attachment position of the fan is inclined in the flowing direction of the air current. The protruding heights of the radiation fins vary in accordance with the inclination angle of the wall, so that the top ends of the radiation fins formed on the outer surface of the inclined wall are aligned in line. In this structure, a wide enough space can be ensured for attaching the fan in the casing, and the outer surface area of the casing can be prevented from becoming large.
Also, according to the present invention, one of a first connecting terminal and a second connecting terminal is movably set in a direction perpendicular to an insertion direction. During the process of connecting the first connecting terminal to the second connecting terminal, the first and second connecting terminals can be positioned relatively with each other. In this structure, even if the first connecting terminal is inserted at a location slightly deviated from the second connecting terminal, the connection between the first and second connecting terminals can be established.
Further, according to the present invention, one of the first connecting terminal and the second connecting terminal has tapered guide pins that extend in the insertion direction, while the other one has positioning guide holes to be engaged with the guide pins. Through the engaging process between the guide pins and the guide holes, the first and second connecting terminals are positioned relatively with each other. Thus, the first connecting terminal can be connected without fail to the second connecting terminal.
The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.